The present invention is directed to a method and apparatus for promoting uniform healthy development of a growing crop by providing a variable rate application of agricultural chemicals, including fertilizer and pesticides, such as insecticides, fungicides and herbicides, to a cultivated field. In particular, the invention provides a method for achieving optimized crop development using a minimum necessary amount of agricultural chemicals, adapted specifically to spatial variations in crop vigor.
Systems for variable rate application of fertilizer to a field which is under cultivation are known. For example, U.S. Pat. No. 5,220,876 discloses a variable rate fertilizer spreading apparatus that uses a soil map, (which may be acquired, for example, from an aerial infrared photograph), in order to determine the amount of fertilizer that is to be applied at each location within the field. For this purpose, a map is prepared (referred to as a xe2x80x9cfertilizer mapxe2x80x9d), which shows a spatially distributed desired fertilizer level throughout the field, as well as a xe2x80x9cstatusxe2x80x9d map which shows corresponding existing fertilizer distribution throughout the field. The desired distribution of fertilizer as recorded in the xe2x80x9cfertilizer mapxe2x80x9d is prepared in advance, based on determined physical characteristics of the field itself, including field topography, soil type, drainage, sun exposure, and the like. In order to provide for application of the proper amount of fertilizer to achieve the desired distribution, an xe2x80x9cExpert Systemxe2x80x9d utilizes artificial intelligence to perform the necessary calculations, based on the fertilizer map, the status map, the soil type and the types of chemicals that are being applied.
In a prescription forming control system disclosed in U.S. Pat. No. 5,919,242, a navigation controller controls the delivery rate of agricultural products by an applicator vehicle, as a function of the global position of the vehicle, based on digital maps which divide a field into xe2x80x9czonesxe2x80x9d, according for example to soil types. Several different products are delivered at differing rates depending on the soil content and the types of crops that are being cultivated. Similarly, U.S. Pat. No. 5,913,915 also discloses a multi-variable dispensing rate applicator for agricultural products in which a computerized control system stores a digital soil map containing information concerning the location of types of soils, topographic features, nutrient levels, soil compaction, drainage and the like. A map coordinate system allows for variable input control from side to side relative to the movement of the applicator system.
U.S. Pat. No. 6,199,000 B1 provides a precision farming method in which seeding, cultivating and/or harvesting operations are controlled using GPS technology in conjunction with a digital map of an agricultural field, which may be created using satellite, aircraft or other overhead imagery. High resolution photographs acquired in this manner are used to generate the digital map. According to this disclosure, relevant information can then be stored in the map (location of irrigation systems, previous planting locations of other crops and the like), and used to determine, for example, the location at which new crops/seeds should be planted.
Similar systems, in which soil characteristic maps are used to control automated agricultural machines are disclosed in U.S. Pat. Nos. 6,236,907 B1; 6,336,066 B1 and 6,141,614.
Each of the above prior art systems is based on the premise that the likely development of a crop planted in a particular field (and therefore the amount of nutrients which should be added in order to achieve optimum plant growth) can be calculated based on physical soil and field conditions, such as the type of soil, topography, drainage, existing nutrient levels, compaction, etc. Accordingly, such information concerning soil and field conditions is stored in the form of a map or maps, which are then used to determine an optimum distribution of fertilizer or the like, based on complex, in some cases proprietary, algorithms. (See, for example, U.S. Pat. No. 5,220,876 at Column 8, lines 58 et seq.)
Such systems share the common deficiency that they reflect only the soil and other physical field characteristics, and in some instances the type of crop being cultivated. While these may be reasonable prognosticators of likely crop development, they do not and cannot take into account or adjust for actual crop growth due, for example, to the effects of weather, diseases, insects and the like. Nor can they take into account the effects of weather on the materials themselves after they have been appliedxe2x80x94such as for example due to heavy rains and attendant runoff. They are also generally incapable of generating time variable dynamic crop prescriptions based on actual crop development throughout the growing season.
Accordingly, it is an object of the present invention to provide a method and apparatus for controlling a spatially variable rate delivery apparatus for applying agricultural chemicals to a growing crop in a cultivated field which dynamically takes into account actual crop development throughout the growing season. (As used herein, the term xe2x80x9cspatially variable ratexe2x80x9d means that the rate at which agricultural chemicals are applied varies as a function of geographic position, and includes so called xe2x80x9con/offxe2x80x9d systems, in which application is varied between zero (xe2x80x9coffxe2x80x9d) and a fixed application rate (xe2x80x9conxe2x80x9d), depending on position.)
Another object of the invention is to provide such a method and apparatus for controlling application rates for agricultural chemicals, which automatically takes into account the effects of weather, disease and insects on crop development.
Another object of the invention is to provide such a system which is responsive to the effects of weather on the agricultural chemicals themselves, after they have been applied.
Yet another object of the invention is to provide a system that can be used to control application rates for pesticides, including herbicides, insecticides and fungicides, in addition to fertilizers.
Still a further object of the invention is to provide a system that can be correlated with ground truth information for accurate decision making.
Another object of the invention is to eliminate the necessity of storing large volumes of soil status information in the form of multilayer maps, as well as the need for complex calculations based on such maps. (It is of course apparent that such additional xe2x80x9clayersxe2x80x9d of information may prove useful, and may therefore be used optionally.)
These and other objects and advantages are achieved by the method and apparatus according to the invention, in which remotely sensed spectral image data are used to develop a Vegetation Index image that represents spatial variations of actual crop vigor throughout a field that is under cultivation. Such a Vegetation Index may, for example, be a conventional xe2x80x9cNormalized Difference Vegetation Indexxe2x80x9d, or any other band combination which yields spatially resolved information regarding the vigor of existing vegetation. Moreover, as used herein, the term xe2x80x9cspectral image dataxe2x80x9d encompasses all types of spectrally resolved image data, including data sets that are conventionally referred to as xe2x80x9cmultispectralxe2x80x9d and xe2x80x9chyperspectralxe2x80x9d imagery, as well as any equivalent spectrally resolved image data.
The latter information is processed to place it in a format that can be used by farm personnel to correlate and calibrate it with actually observed crop conditions existing at control points within the field. Based on the results, farm personnel formulate a prescription request, which is forwarded via email (or other communications medium) to a central processing site, where the prescription is prepared. The latter is returned via email (or other medium) to on site farm personnel, who can load it into a controller on a spray rig that directly applies inputs to the field.
Other objects, advantages and novel features of the present invention will become apparent from the following detailed description of the invention when considered in conjunction with the accompanying drawings.